This invention relates to the attachment of lath to a support. In particular, the invention involves the use of a screw and a spacing element to leave a space between the lath and the support. The invention is directed to the fastener as well as a tool specially designed to install the fastener.
Current techniques for attaching lath have been found to be quite unsatisfactory. Installers of lath frequently use scrap material as a shim between the lath and the support, and then apply standard screws to hold the lath against the shim. With this technique, it is frequently the case that a workman will not provide a space between the lath and its support, because scrap material may not be available, or because it may be difficult to hold a shim in place while installing a piece of lath of significant lateral extent. It should be noted that architects and building codes frequently require that a space be provided between lath and a support. The spacing is important because it provides a place for plaster to extrude when it is applied to the lath. Without proper spacing at locations where the lath is supported, the thickness of the plaster will not be sufficient, and unsightly cracking will be much more likely to occur.
It is, therefore, an object of the present invention to provide a fastener for attaching lath to a support.
Another object of the invention is to provide a tool for installing fasteners in accordance with the present invention.
Another object of the invention is to provide a fastener which will enable the attachment of lath to a variety of supports including supports of both metallic and non-metallic materials.
Another object of the invention is to provide a spacing element for use with a screw to attach lath to a support.
Another object of the invention is to provide a unitary screw-like fastener which can be used to spacingly attach lath to a support.
These and other objects and advantages of the invention are achieved by using a screw with a head at one end and a tip at the other. A spacing element associated with the screw is generally helically shaped and is adapted to threadingly engage the lath and lift the lath away from the support. The spacing element may be separate from the screw, preassembled to the tip of the screw, or integrally formed along the shank of the screw. The spacing element, however, preferably includes a tapering helix in order to facilitate engagement of the spacing element with the lath. The invention also involves the use of a special tool which includes a generally tubular element which is attachable to a driving tool. The tubular portion includes at least one prong-like element extending axially from the free end thereof. In the preferred embodiment of the fastener of the present invention, a spacing element comprised of a helical coil is preassembled to the screw at a location adjacent to the tip of the screw. The screw preferably includes a drill tip. As the screw is used to drill a hole in the support, the spacing element makes its way through the lath and abuts the support. The screw penetrates both the support and the spacing element. When proper penetration of the screw into the support has taken place, continued axial advancement of the screw is stopped, and the lath is held between the head of the screw and upper portions of the spacing element. The tool is adapted to automatically disengage from the head of the screw at a predetermined point.